Establishing a product rating table for the grocery shopping system in MySQL

Establish a product rating table for the food shopping system in MySQL

In the food shopping system, product rating is an important function that can help users understand the quality and word-of-mouth to make better purchasing decisions. In order to implement this function, we need to create a product rating table in the MySQL database. The following will introduce in detail how to create this table and give specific code examples.

First, we need to determine the fields of the product rating table. Commonly used fields include product ID, user ID, rating level, evaluation content and evaluation time. Based on these fields, we can create a table named "product_rating". The specific code is as follows:

CREATE TABLE product_rating (
    id INT AUTO_INCREMENT PRIMARY KEY,
    product_id INT NOT NULL,
    user_id INT NOT NULL,
    rating FLOAT NOT NULL,
    review TEXT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

In the above code, we use MySQL's "CREATE TABLE" statement to create a table named "product_rating" table. The table contains the following fields:

• id: evaluation ID, as the primary key, each evaluation record has a unique ID.
• product_id: product ID, used to associate specific products.
• user_id: User ID, used to associate with a specific user.
• rating: Rating, using floating point type to represent the rating, which can be any value between 0 and 5.
• review: Review content, use TEXT type to store long text.
• created_at: Evaluation time, the default value is the current timestamp, used to record the creation time of the evaluation.

Next, we can add a foreign key constraint in the product table to associate the "product_id" field of the product rating table "product_rating" with the product ID in the product table. The specific code is as follows:

ALTER TABLE product_rating
    ADD FOREIGN KEY (product_id)
    REFERENCES products(id)
    ON DELETE CASCADE;

In the above code, we use MySQL's "ALTER TABLE" statement and use the "ADD FOREIGN KEY" clause to combine the "product_id" field of "product_rating" with the "products" The "id" field is associated. Among them, the keyword "REFERENCES" means referencing the associated table, and the keyword "ON DELETE CASCADE" means that when the product is deleted, the related evaluation records will also be deleted.

Finally, we can also add a foreign key constraint in the user table to associate the "user_id" field of the product rating table "product_rating" with the user ID in the user table to ensure that the evaluation record is related to the specific User association. The specific code is as follows:

ALTER TABLE product_rating
    ADD FOREIGN KEY (user_id)
    REFERENCES users(id)
    ON DELETE CASCADE;

In the above code, we use MySQL's "ALTER TABLE" statement and use the "ADD FOREIGN KEY" clause to combine the "user_id" field of "product_rating" with the "users" field. The "id" field is associated. Among them, the keyword "REFERENCES" means referencing the associated table, and the keyword "ON DELETE CASCADE" means that when a user is deleted, the related evaluation records will also be deleted.

Through the above steps, we successfully created a product rating table named "product_rating" in the MySQL database and established a relationship with the product table and user table. In this way, we can use this table in the grocery shopping system to implement the product rating function.

Summary:

The product rating function of the grocery shopping system is very important for users. It can help users understand the quality and reputation of the products. We can achieve this function by creating a product rating table in the MySQL database and associating it with the product table and user table. The above is a specific code example for establishing a product rating table for the grocery shopping system in MySQL.

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